California investigators tracked down the man they suspect is the Golden State Killer by comparing crime scene DNA to information on genealogy websites consumers use to trace their ancestry, a prosecutor said on Thursday. Former police officer Joseph James DeAngelo, 72, was arrested on Tuesday outside the Sacramento-area home where he has lived for at least two decades, not far from the site of the first of eight murders he is charged with committing 40 years ago. DeAngelo, described by neighbors as an oddball and loner known to fly into occasional fits of solitary rage, is suspected of 12 slayings in all.